[ClusterLabs] group resources without order behavior / monitor timeout smaller than interval?

[Ken Gaillot]

On 09/20/2016 05:06 AM, Dejan Muhamedagic wrote:
> Hi,
> 
> On Wed, Sep 14, 2016 at 02:41:10PM -0500, Ken Gaillot wrote:
>> On 09/14/2016 03:01 AM, Stefan Bauer wrote:
>>> Hi,
>>>
>>> I'm trying to understand some cluster internals and would be happy to
>>> get some best practice recommendations:
>>>
>>> monitor interval and timeout: shouldn't timeout value always be smaller
>>> than interval to avoid another check even though the first is not over yet?
>>
>> The cluster handles it intelligently. If the previous monitor is still
>> in progress when the interval expires, it won't run another one.
> 
> The lrmd which got replaced would schedule the next monitor
> operation only once the current monitor operation finished, hence
> the timeout value was essentialy irrelevant. Is that still the
> case with the new lrmd?

Oh, you're right -- the interval starts from when the last monitor
completed. So it doesn't matter if the timeout is longer than the interval.

> 
>> It certainly makes sense that the timeout will generally be smaller than
>> the interval, but there may be cases where a monitor on rare occasions
>> takes a long time, and the user wants the high timeout for those
>> occasions, but a shorter interval that will be used most of the time.
> 
> Just to add that there's a tendency to make monitor intervals
> quite short, often without taking a good look at the nature of
> the resource.
> 
> Thanks,
> 
> Dejan
> 
>>> Additionally i would like to use the group function to put all my VMS
>>> (ocf:heartbeat:VirtualDomain) in one group and colocate the group with
>>> the VIP and my LVM-volume. Unfortunately group function starts the
>>> resources in the listed order. So if i stop one VM, the following VMs
>>> are also stopped.
>>>
>>> Right now I'm having the following configuration and want to make it
>>> less redundant:
>>
>> You can use one ordering constraint and one colocation constraint, each
>> with two resource sets, one containing the IP and volume with
>> sequential=true, and the other containing the VMs with sequential=false.
>> See:
>>
>> http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#s-resource-sets
>>
>>
>>>
>>> # never let the stonith_service run on the host to stonith
>>>
>>> location l_st_srv20 st_ipmi_srv20 -inf: srv20
>>> location l_st_srv21 st_ipmi_srv21 -inf: srv21
>>>
>>>
>>> # do not run resources on quorum only node
>>> location loc_r_lvm_vg-storage_quorum_only_node r_lvm_vg-storage -inf:
>>> quorum_only_node
>>> location loc_r_vm_ado01_quorum_only_node r_vm_ado01 -inf: quorum_only_node
>>> location loc_r_vm_bar01_quorum_only_node r_vm_bar01 -inf: quorum_only_node
>>> location loc_r_vm_cmt01_quorum_only_node r_vm_cmt01 -inf: quorum_only_node
>>> location loc_r_vm_con01_quorum_only_node r_vm_con01 -inf: quorum_only_node
>>> location loc_r_vm_con02_quorum_only_node r_vm_con02 -inf: quorum_only_node
>>> location loc_r_vm_dsm01_quorum_only_node r_vm_dsm01 -inf: quorum_only_node
>>> location loc_r_vm_jir01_quorum_only_node r_vm_jir01 -inf: quorum_only_node
>>> location loc_r_vm_jir02_quorum_only_node r_vm_jir02 -inf: quorum_only_node
>>> location loc_r_vm_prx02_quorum_only_node r_vm_prx02 -inf: quorum_only_node
>>> location loc_r_vm_src01_quorum_only_node r_vm_src01 -inf: quorum_only_node
>>>
>>>
>>> # colocate ip with lvm storage
>>> colocation col_r_Failover_IP_r_lvm_vg-storage inf: r_Failover_IP
>>> r_lvm_vg-storage
>>>
>>>
>>> # colocate each VM with lvm storage
>>> colocation col_r_vm_ado01_r_lvm_vg-storage inf: r_vm_ado01 r_lvm_vg-storage
>>> colocation col_r_vm_bar01_r_lvm_vg-storage inf: r_vm_bar01 r_lvm_vg-storage
>>> colocation col_r_vm_cmt01_r_lvm_vg-storage inf: r_vm_cmt01 r_lvm_vg-storage
>>> colocation col_r_vm_con01_r_lvm_vg-storage inf: r_vm_jir01 r_lvm_vg-storage
>>> colocation col_r_vm_con02_r_lvm_vg-storage inf: r_vm_con02 r_lvm_vg-storage
>>> colocation col_r_vm_dsm01_r_lvm_vg-storage inf: r_vm_dsm01 r_lvm_vg-storage
>>> colocation col_r_vm_jir01_r_lvm_vg-storage inf: r_vm_con01 r_lvm_vg-storage
>>> colocation col_r_vm_jir02_r_lvm_vg-storage inf: r_vm_jir02 r_lvm_vg-storage
>>> colocation col_r_vm_prx02_r_lvm_vg-storage inf: r_vm_prx02 r_lvm_vg-storage
>>> colocation col_r_vm_src01_r_lvm_vg-storage inf: r_vm_src01 r_lvm_vg-storage
>>>
>>> # start lvm storage before VIP
>>>
>>> order ord_r_lvm_vg-storage_r_Failover_IP inf: r_lvm_vg-storage r_Failover_IP
>>>
>>>
>>> # start lvm storage before each VM
>>> order ord_r_lvm_vg-storage_r_vm_ado01 inf: r_lvm_vg-storage r_vm_ado01
>>> order ord_r_lvm_vg-storage_r_vm_bar01 inf: r_lvm_vg-storage r_vm_bar01
>>> order ord_r_lvm_vg-storage_r_vm_cmt01 inf: r_lvm_vg-storage r_vm_cmt01
>>> order ord_r_lvm_vg-storage_r_vm_con01 inf: r_lvm_vg-storage r_vm_con01
>>> order ord_r_lvm_vg-storage_r_vm_con02 inf: r_lvm_vg-storage r_vm_con02
>>> order ord_r_lvm_vg-storage_r_vm_dsm01 inf: r_lvm_vg-storage r_vm_dsm01
>>> order ord_r_lvm_vg-storage_r_vm_jir01 inf: r_lvm_vg-storage r_vm_jir01
>>> order ord_r_lvm_vg-storage_r_vm_jir02 inf: r_lvm_vg-storage r_vm_jir02
>>> order ord_r_lvm_vg-storage_r_vm_prx02 inf: r_lvm_vg-storage r_vm_prx02
>>> order ord_r_lvm_vg-storage_r_vm_src01 inf: r_lvm_vg-storage r_vm_src01
>>>
>>> any help is greatly appreciated.
>>>
>>> thank you.
>>>
>>> Stefan